{PDOC51493}
{PS51493; AV_NSP4_PRO}
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* Arterivirus nsp4 proteinase domain profile *
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Arteriviruses are   enveloped,   positive-stranded  RNA  viruses  and  include
pathogens of   major   economic  concern  to  the  swine-  and  horse-breeding
industries [E1]:

  - Equine arteritis virus (EAV).
  - Porcine reproductive and respiratory syndrome virus (PRRSV).
  - Mice actate dehydrogenase-elevating virus.
  - Simian hemorrhagic fever virus.

The arterivirus  replicase  gene encodes two large precursor polyproteins that
are processed by the viral main proteinase nonstructural protein 4 (nsp4). The
structure of  the  enzyme  reveals  two  chymotrypsin-like  antiparallel beta-
barrels and  an  extra  C-terminal  alpha/beta  domain that may play a role in
mediating protein-protein  interactions  (see  <PDB:1MBM;  A>). The N-terminal
barrel consists of six beta-strands (A1 to F1), while the C-terminal barrel is
composed of  seven  (A2  to G2). The core of both beta-barrels is comprised of
conserved hydrophobic  residues.  The additional C-terminal domain consists of
two pairs   of  short  antiparallel  beta-sheets  and  two  alpha-helices.  It
interacts with  the  C-terminal  barrel  through  an  interface  consisting of
conserved hydrophobic  residues.  A canonical catalytic triad that is composed
of Ser,  His,  and  Asp  is located in the open cleft between the beta-barrels
domain [1,2]. The nsp4 proteinase domain forms peptidase family S32 [E2].

The profile we developed covers the entire nsp4 proteinase domain.

-Sequences known to belong to this class detected by the profile: ALL.
-Other sequence(s) detected in Swiss-Prot: NONE.
-Last update: May 2010 / First entry.

[ 1] Barrette-Ng I.H., Ng K.K.S., Mark B.L., van Aken D., Cherney M.M.,
     Garen C., Kolodenko Y., Gorbalenya A.E., Snijder E.J., James M.N.G.
     "Structure of arterivirus nsp4. The smallest chymotrypsin-like
     proteinase with an alpha/beta C-terminal extension and alternate
     conformations of the oxyanion hole."
     J. Biol. Chem. 277:39960-39966(2002).
     PubMed=12163505; DOI=10.1074/jbc.M206978200
[ 2] Tian X., Lu G., Gao F., Peng H., Feng Y., Ma G., Bartlam M., Tian K.,
     Yan J., Hilgenfeld R., Gao G.F.
     "Structure and cleavage specificity of the chymotrypsin-like serine
     protease (3CLSP/nsp4) of Porcine Reproductive and Respiratory Syndrome
     Virus (PRRSV)."
     J. Mol. Biol. 392:977-993(2009).
     PubMed=19646449; DOI=10.1016/j.jmb.2009.07.062
[E1] https://viralzone.expasy.org/284?outline=all_by_species
[E2] https://www.ebi.ac.uk/merops/cgi-bin/famsum?family=s32

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